Animation (VIDEO) Delft University of Technology This video is under embargo. Please login to access this video. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Caption The child's puzzle can be used to explain Nagaoka ferromagnetism. The puzzle on the left shows that every shuffle changes the spin configuration. The puzzle on the right shows all the spins aligned, which lowers the energy of the system. Credit Scixel de Groot for QuTech Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.